The present invention relates generally to the field of explosives, propellants and pyrotechnics and more particularly to reducing the hazards of handling, manufacturing, storage, transporting, using and demolition of these materials.
Since the time of Nobel, much effort in research and development has been expanded to develop more efficient and reliable explosives. These ends have been achieved in part, but little or no real comparable progress has been made until the instant invention in the area of hazard prevention in the manufacture, storage, transportation, demolition and demilitarization of explosives, propellants and pyrotechnics commensurate with the development of these materials.
In the manufacture of these materials the hazards were and still are being viewed as being existant and that explosive and conflagration accidents are inevitable and unavoidable. The objective, until the present invention, has been to minimize them. This has been done by providing manufacturing buildings with concrete walls 3 feet thick. Roofs and ceilings have been designed with like strength and like safety factors, or alternatively designed to blow off. Internally, certain precautions have been taken. For example, 1 foot thick concrete or cement block dividing walls have been used to partially localize accidental blasts and fires. The affects of blasts such as overpressure and the effects of rapid fires are generally vented out doors, above the dividing walls, or through a portion of the roof which is designed to give way. One contemporary installation has an outside wall which extends from one dividing wall to the other built of frangible material so that the pressures from the blast and fires are vented therethrough. Other wall designs instead of pure concrete are also in use. The concrete walls have been reinforced with welded steel reinforcements which enables the concrete to withstand more explosive force in as much as it is weak in tension. Alternatively, hollow walls have been constructed and used with some success. They comprise spaced inner and outer panels of either steel or wood with sand filling the space therebetween. The assembly lines are generally segmentized in plural of the aforementioned buildings and for within each building structure. This is and has been done with safety in mind; i.e., in the event of an explosion and/or fire only one portion of the assembly line is destroyed. Within one building structure it is conventional to pass the assembly line transverse to and through these dividing walls. Through heavy wall and divider construction, a measure of hazard prevention has been bad. Even in view thereof, ever present danger to personnel life and plant demolition still plagues the explosive propellant and pyrotechnic manufacturing community. This is so, because the concept of Quantity-Distance (Q-D) is still the only guide employed to protect adjacent structures against major structural damage.
In the storage of partially or fully assembled, munitions and explosives, it is and has been common practice to provide storage magazines under the earth. The magazine comprises a concrete structure with an entrance way, with walls, a floor, and a roof 2 to 3 feet thick. The roof is generally dome shaped and the entrance way is closed by a heavy door which is designed to give way if a blast occurs. The roof is generally covered with 3 to 4 feet of packed earth. Though a measure of safety is had by these storage efforts, the possibility of explosive blasts and fires causing harm to persons and property considerable distances from the storage area still exists.
In the field of transporting explosives, propellants, pyrotechnics and munitions, where the material or the munition either has deteriorated to an unsafe condition or it has become obsolete, very uneconomical and stringent safety measures are and have been taken. Isolated and uninhabited sites in the plains and within valleys with high ground or mountainous perimeters have served this end. So also, strong structures with high safety factors have been neutralizing, "provided for blasts", where the above sites are inaccessible or the economic factors make it prohibitive. Though these measures have served to prevent harm to the general population and to valuable real and personal property, real and present danger always exists to the needed personnel. Aside from the use of all-metal, imperforate, thick shields between the exploding medium and the personnel doing the detonating, tremendous danger exists due to flying debris (fragments, firebrands, etc) and from the flame or fire effects.
The effort to alleviate and eliminate harm to persons and property, as outlined above has led us to the development of our new explosive and fire shielding techniques which we believe are a brake-through in hazard protection and prevention in the explosive, propellant and pyrotechnic fields. Until the instant, confinement of the explosion or fire in its entirety was the aim. Thus the percussion forces resulting from the rapid release of energy caused conflagration and debris to be spread over a wide area. This required the specification of "quantity distance" which necessitates large areas of real estate to be set aside as buffer zones in order to achieve a safe environment. Our invention is a departure therefrom. We, according to our invention, confine 100% of the flying debris (fragments) within the immediate vicinity of the explosion and bleed off, or dissipate, and baffle the pressure differential to reduce the force thereof to a negligible level. By the use of our innovative shield, hazards of blasts and combustion will be reduced ten fold. With our invention, personnel working near hazardous material manufacturing, storage, demilitarization and demolition areas and those using and transporting hazardous materials will be able to survive resulting explosions, blasts, and fires of these materials with little or no personal harm.